Gl. Newton et al., POLYAMINE-INDUCED COMPACTION AND AGGREGATION OF DNA - A MAJOR FACTOR IN RADIOPROTECTION OF CHROMATIN UNDER PHYSIOLOGICAL CONDITIONS, Radiation research, 145(6), 1996, pp. 776-780
Spermine at physiological levels and ionic strength induces compaction
and aggregation of SV40 DNA and minichromosomes resulting in marked r
adioprotection of the DNA against gamma-ray-induced formation of singl
e-strand breaks. This phenomenon, termed the PICA effect, results in y
ields of single-strand breaks in DNA and minichromosomes comparable to
those found with intact cells and is considered to be a major mechani
sm responsible for radioprotection of cellular DNA. (C) 1996 by Radiat
ion Research Society